Techniques for beam selection based on measurement periodicities

Abstract

Methods, systems, and devices for wireless communications are described in which a user equipment (UE) may perform beam measurements for one or more subsets of beams that are selected to provide enhanced beam switch determinations. The UE may identify one or more prioritized beams, and may measure the prioritized beams at a same periodicity as measurements of a serving beam. The UE may, additionally or alternatively, identify a set of all layer one beams (e.g., maximum-level beams or top level beams) for measurement according to a periodic interval, based on a measured mobility being less than a threshold value. The periodic interval may provide that each layer one beam may be measured at a cadence of one beam per measurement occasion, in order to provide measurement diversity.

What is claimed is: 
     
         1 . A method for wireless communication at a user equipment (UE), comprising:
 measuring first channel characteristics of a serving beam according to a first periodicity associated with transmission of one or more reference signals using the serving beam, wherein the first channel characteristics of the serving beam are measured on a per synchronization signal block (SSB) basis;   selecting one or more candidate beams from a set of available beams for measurement according to the first periodicity, the one or more candidate beams selected based at least in part on a signal strength of beams of the set of available beams;   measuring second channel characteristics of each of the one or more candidate beams according to the first periodicity, wherein the second channel characteristics of the each of the one or more candidate beams are measured on a per synchronization signal block (SSB) basis; and   triggering a beam switch to a first candidate beam of the one or more candidate beams based at least in part on the first channel characteristics of the serving beam being below a threshold value.   
     
     
         2 . The method of  claim 1 , wherein the measurement of the one or more candidate beams at the first periodicity provides consistent sampling and filtering of the one or more candidate beams and the serving beam for equivalent comparison of associated channel characteristics. 
     
     
         3 . The method of  claim 1 , wherein the one or more candidate beams include up to a determined quantity of beams of the set of available beams that are within a measurement difference threshold of the serving beam. 
     
     
         4 . The method of  claim 3 , further comprising:
 updating the selected one or more candidate beams after each measurement period of the first periodicity.   
     
     
         5 . The method of  claim 4 , wherein each measurement period includes a set of measurement occasions and one or more beams other than the one or more candidate beams are measured in a measurement period when fewer candidate beams than measurement occasions are present. 
     
     
         6 . The method of  claim 1 , wherein one or more beams of the set of available beams other than the one or more candidate beams are selected for inclusion in a prioritized subset of beams based on one or more previous measurement metrics, a codebook hierarchy, or any combinations thereof. 
     
     
         7 . The method of  claim 6 , wherein the one or more previous measurement metrics identify the prioritized subset of beams as beams having one or more of a reference signal received power (RSRP) or signal to noise ratio (SNR) that exceed corresponding measurement metrics of other beams by a determined amount, and wherein the codebook hierarchy indicates one or more beams that are associated with the serving beam. 
     
     
         8 . The method of  claim 1 , wherein the selecting of the one or more candidate beams is based at least in part on a detected mobility of the UE exceeding a threshold mobility value. 
     
     
         9 . A method for wireless communication at a user equipment (UE), comprising:
 selecting a first subset of beams from a set of available beams based at least in part on codebook hierarchy associated with a first beam having one or more channel metrics that exceed corresponding channel metrics of other beams of the set of available beams, wherein the first subset of beams are prioritized for channel measurements;   determining that a mobility of the UE is less than a threshold value;   selecting, based at least in part on the determining, a second subset of beams from the set of available beams, the second subset of beams including highest level parent beams of the set of available beams, wherein one or more beams of the first subset of beams are scheduled for measurement in measurement occasions that are unused for measurement of one or more beams of the second subset of beams;   measuring channel characteristics for each beam of the first subset of beams at a first measurement interval, and measuring channel characteristics for each beam of the second subset of beams at a second measurement interval having a longer periodicity than the first measurement interval; and   triggering a beam switch to a first candidate beam of the second subset of beams based at least in part on the first candidate beam having measured channel characteristics that exceed corresponding channel characteristics of each beam of the first subset of beams.   
     
     
         10 . The method of  claim 9 , wherein the codebook hierarchy indicates one or more parent beams, child beams, neighbor beams, or any combinations thereof, associated with the first beam. 
     
     
         11 . The method of  claim 9 , wherein the first beam is selected based at least in part on being associated with a boresight of an antenna panel of the UE having a line-of-sight (LoS) with an access network entity antenna, one or more measurement metrics, or any combinations thereof. 
     
     
         12 . The method of  claim 9 , wherein the codebook hierarchy is a union of all adjacent beam relationships to the first beam in a codebook provided by an access network entity based at least in part on freespace beam characteristics. 
     
     
         13 . The method of  claim 9 , wherein the second measurement interval corresponds to one beam of the second subset of beams per each first measurement interval. 
     
     
         14 . The method of  claim 13 , wherein each beam of the second subset of beams is measured once per a quantity of second measurement intervals that corresponds to a quantity of beams in the second subset of beams. 
     
     
         15 . The method of  claim 9 , wherein the second measurement interval is selected to provide for one or more measurements of each beam of the first subset of beams at a higher periodicity than measurements of each beam of the second subset of beams. 
     
     
         16 . The method of  claim 9 , wherein the mobility of the UE is determined based at least in part on an inertial measurement unit (IMU) sensor measurement value, and wherein the threshold value is associated with a relatively slow or no UE movement as measured at the IMU. 
     
     
         17 . The method of  claim 9 , wherein the measuring channel characteristics for the second subset of beams provides for the beam switch to be performed in an event of a hand blockage associated with the first subset of beams. 
     
     
         18 . A method for wireless communication at a user equipment (UE), comprising:
 identifying a first subset of beams from a set of available beams for channel measurements based at least in part on a first serving beam used for communications with an access network entity;   selecting, based at least in part on a mobility of the UE, a second subset of beams that includes one or more other beams outside of the first subset of beams for periodic channel measurements, wherein the second subset of beams includes a prioritized subset of beams based on previous measurement metrics or top-level beams included in a codebook of beams, wherein the second subset of beams includes one or more beams that are selected for inclusion in the prioritized subset of beams based on one or more previous measurement metrics;   measuring channel characteristics for the first subset of beams and the second subset of beams at a measurement interval; and   triggering a beam switch to a first candidate beam of the first subset of beams or the second subset of beams based at least in part on the first candidate beam having higher measured channel characteristics than other measured channel characteristics of the first subset of beams and the second subset of beams.   
     
     
         19 . The method of  claim 18 , wherein the one or more previous measurement metrics identify the prioritized subset of beams as beams having one or more of a reference signal received power (RSRP) or signal to noise ratio (SNR) that exceed corresponding measurement metrics of other beams by a determined amount. 
     
     
         20 . The method of  claim 18 , wherein the first subset of beams includes one or more parent beams, child beams, neighbor beams, or any combinations thereof, associated with the first serving beam. 
     
     
         21 . The method of  claim 18 , wherein the first serving beam is selected based at least in part on being associated with a boresight of an antenna panel of the UE having a line-of-sight (LoS) with an access network entity antenna, one or more measurement metrics, or any combinations thereof. 
     
     
         22 . The method of  claim 18 , wherein one or more beams of the first subset of beams are scheduled for measurement in measurement occasions that are unused for measurement of one or more beams of the second subset of beams. 
     
     
         23 . An apparatus for wireless communication at a user equipment (UE), comprising:
 a processor;   memory coupled with the processor; and   instructions stored in the memory and executable by the processor to cause the apparatus to:
 measure first channel characteristics of a serving beam according to a first periodicity associated with transmission of one or more reference signals using the serving beam, wherein the first channel characteristics of the serving beam are measured on a per synchronization signal block (SSB) basis; 
 select one or more candidate beams from a set of available beams for measurement according to the first periodicity, the one or more candidate beams selected based at least in part on a signal strength of beams of the set of available beams; 
 measure second channel characteristics of each of the one or more candidate beams according to the first periodicity, wherein the second channel characteristics of the each of the one or more candidate beams are measured on a per synchronization signal block (SSB) basis; and 
 trigger a beam switch to a first candidate beam of the one or more candidate beams based at least in part on the first channel characteristics of the serving beam being below a threshold value. 
   
     
     
         24 . The apparatus of  claim 23 , wherein the measurement of the one or more candidate beams at the first periodicity provides consistent sampling and filtering of the one or more candidate beams and the serving beam for equivalent comparison of associated channel characteristics. 
     
     
         25 . The apparatus of  claim 23 , wherein the one or more candidate beams include up to a determined quantity of beams of the set of available beams that are within a measurement difference threshold of the serving beam. 
     
     
         26 . The apparatus of  claim 25 , wherein the instructions are further executable by the processor to cause the apparatus to:
 update the selected one or more candidate beams after each measurement period of the first periodicity.